This field study was conducted along a curve where the barrier line was worn out due to encroachments by cars. Vehicles were unobtrusively video recorded with the worn barrier line, after re-painting the barrier line and after milling the rumble strip barrier line. Lateral positions and speeds of vehicles were measured. Vehicle type and traffic situation were also classified (n = 6599). It was assumed that if encroachments of barrier line and the standard deviation of lateral positions were reduced, safety would improve. The standard deviation of the lateral position of passenger cars travelling in free-flow traffic decreased from 35 cm with the worn barrier line to 28 cm after re-painting the barrier line and to 24 cm after milling the rumble strip barrier line. The mean speeds of cars in free-flow traffic did not change. No vehicle with oncoming traffic crossed the barrier line after rumble strip. Encroachments of passenger cars in free-flow traffic with no oncoming traffic fell from 9.2% to 2.5% after re-painting, with no further change after implementing the rumble strip. The improvement in visual guidance alone reduced the number of crossings. However, including rumble strips may reduce the need for frequent re-painting of barriers. (A) "Reprinted with permission from Elsevier".
Abstract